Combined radio receiving and intercommunication system



Jly 4, 1939. K. E. sTocK'roN Er ALA 2,154,950 l COMBINED4 RADIO RECEIVING AND INTERCOMMUNIATION SYSTEM Filed Feb. 27, 1937 3 Sheets-Sheet 1 lNvENToRs KENNETH E. STOCKTON. v BY JACOB S. JAP'I'NER v ATTORNEY July 4, '1939. K.. 'STOCKTON ET AL 2,164,960

COMBINED RADIO REEIVING AND INTERCOMMUNICATION SYSTEM lNvENToRS KENNETH E. STOCKTON BY JACOB 5.JAMMER ATTORNEY K. E. sTocKToN E -r AL" 2,164,960

July 4, 1939.

COMBINED RADIO RECEIVING .AND INTERCOMMUNICTION SYSTEM 3 Sheets-Sheet 3 FIG. 3.

4012/0 Amar/sf? v INVEN-ros KENNETH E. STOCKTON BY JACOB s. JA'mMl-:R ATTORNEY Patented July 4, 1939 ,164,960 AUNITED STATES PATENT OFFICE COMBINED RADIO RECEIVING AND INTERCOM'MUNICATION SYSTEM Application February 27, 1937, Serial No. 128,114

8 Claims. (Cl. 179-1) This invention relates to communication sys' them operative. In Carrying out this Phase of tems and pertains more particularly to systems the invention the circuit arrangement may he of this character which are adapted to utilize Suoh, that in response to the operation of the parts of standard radio receiving omioretus,v inter-communication control switch, the energy .fr while at the same time leaving said apparatus in Will be supplied to only the radio receiver adJ'a- 5 condition for use in receiving radio signals, cent to the inter-communication switch or to the It is an object of our invention to provide receiver remote from the inter-communication means whereby two radio receiving setsI suon switch, orto both of these receivers. for example, as might ordinarily be used in sep- Referring to our invention in somewhat more l .0 arate rooms of a private home, may be used as a detail it may be pointed out in a general Way. that l means of inter-communication between the two radio receivers usually consist of a radio frepoints at which the sets are located. Cluenoy amplifying Stage, a detecting stage and A further object is to provide means whereby an audio frequency amplifying stage. the output two or more loud speakers connected to a com of the latter Supplying a loud Speaker- The loud 151 mon radio amplifier may be used both to repro- Speaker iS usually of the moving Coll type and l5 duce a radio or other program and also vto transfairly Well adapted to act as a dynamic type Inimit sound between the two points at which the orophone- However any type of loud Speaker loud speakers are located. adapted to operate as a microphone may be used.

In accordance with our invention two stond- In order that intercommunication between the ard radio receivers are provided, these being lopoints at Which tWo Such-receivers are located 20 cated at different points at which it is desired may be carried out. it is necessary in accordance to receive radio programs and between which it with our invention. to provide switching means may be desired to carry on aconversation. These whereby `the loud Speaker 0f the ISt l'eCeiVer vsets may be, for example, located in the masters may be diSConneoted from the output of the and servants quarters of a house and in this case audio frequency amplifier thereof and be conr it wiu ordinaruy be sufiioient to arrange the epnected to the input instead while. at the same 2" paratus, following our invention, in such way that time, the output 0f the amplifier lust mentioned a radio program being received by one or both iS Connected t0 the input of the audio frequency of said-receivers, may be interrupted and a spokamplifier of the Second reoeiver- By this rearen order be transmitted from the masters rerangement of CirCuitS any WOrdS Spoken into the ceiver to the servants receiver. Inother inloud Speaker at the lrSt reCeiVer Will be reprostances it may be desirable not to interrupt the duced in the loud Speaker at the Seoond receiverreceived program but mei-ely to super-impose the Following this arrangement it will be noted that masters voice on the program being received in the voice currents generated by the rSt loud the servants quarters. Or it may be desired to Speaker. Which iS being used aS a microphone, 35

provide for two way communication between the Will be tWee amplified. onee in the amplifying two receivers. stage of the rst receiver and a second time in In fulfilling any one of these conditions circuits the amplifying stage of the second receiver. are provided so that e loud speaker of one re- This need not necessarily be so. but will in many ceiver is used as a microphone for transmitting inStaneeS be found desirable in order t0 obtain 40 voice currents to the audio-frequency amplifier Suflioient Sensitivity of piek-up With'a Suitable ofthe other receiver. Or according to a. modi- Volume of output at the loud Spaker 0f the Seofcation of our invention, by the use of e, hybrid ond receiver. However, in certain instances the coil arrangement, inter-communication between Sound reproduced at the Second 1oud Speaker may two points may be carried on by the aid of two be sufficiently loud if the voice currents from the 45 loud speakers connected to the output of a singlefirst loud speaker are amplified by passing radio receiver or public address system. In this through only one 0f the amplifying Stages of the case, the single amplifier of voice frequency acts two receivers. And this effect may be obtained toamplify the voice currents transmitted from either by connecting the output of the audio ameither of the loud speakers to the other while at pliflcr of the rst receiver directly to the loud the same time, if desired, also amplifying the speaker of the second receiver, or on the other radio program or other signals which are being hand by applying the voice currents generated by transmitted thereto from a remote point. the first loud speaker directly to the input of' the Additional features of our invention involve the audio frequency amplifier of the second receiver.

' provision of control circuits, including relays, It is preferred, however, to use both ampliers 55 whereby upon actuation of a switch which is prosince by this means a suificlent volume of sound vided for the purpose of inter-connecting' the will be obtained, no additional cost of equipment radio receivers to operate as an inter-communibeing involved since both amplifying stages are cation system, the energizing current is supplied available.

o0 from the power source to the receivers to render In carrying out the invention, it is preferable 50 Cil that means likewise be provided for disconnecting the audio frequency stages of the receivers from their respective radio frequency and detecting\stages, whereby interference from an incoming radio program will be prevented. While this operation is preferable in order that ease of communication may result, still .communication may be carried on even though the radio program is still permitted to come through the radio frequency amplifying stages and the detector stages into the audio frequency amplifying stages and the loud speaker of the second receiver. 'Ihe former method of operation has the additional advantage that if the second radio receiver is being used for the reception of the program the interruption of the program will call attention to the fact that intercommunication is desired.

According to a further modification of our invention, intercommunication between two points at which different loud speakers of a common radio receiving set are located, may be carried on. In this modification of our invention, hybrid coils are used to interconnect the two loud speakers with one another as well as with the output and the input of the audio frequency amplifying stage of the receiver. In this'instance the audio frequency amplifying stage just mentioned serves to amplify the speech, whether it is transmitted from the rst loud speaker to the second or from the second t the first. In carrying out this phase of the* invention, it is not necessary that the radio frequency program be interrupted during intercommunication between the two loud speaker points, although such interruption is desirable in order that clear conversation may be carried on with a minimum of difficulty. Tn the event that a radio program is being received or a public address being broadcast, it is merely necessary for a person adjacent one loud speaker to wait for a lull in the program so that vhe may make himself heard with ease at the other loud speaker. Or attention may be attracted by merely tapping on the diaphragm or housing of one loud speaker, which will cause a distinctive sound to be made by the other loud speaker.

In many instances of the use of two loud speakers, one will be connected directly to a radio receiving set and form a part thereof in the usual way, while the ,other loud speaker will be located at a remote point, for example, in another room. -One person of the two carrying on a conversation will, therefore, ordinarily be near to the control mechanism of the receiving set and therefore will be able to detune the receiver so that it no longer picks up a program over the radio aerial which will interfere y with the conversation to be carried on between the two loud speaker points. However, if desirable, push buttons or switches may be located adjacent to each of the loud speakers, whereby through associated circuit connections the audio frequency amplifying stage may be disconnected from the detector and radio frequency stage of the receiver, thereby isolating the circuit for use as an intercommunication system. In this case also, remote control means may be provided adjacent to each of the loud speakers, whereby the audio frequency amplifier may be connected to the power mains or other source of electrical Supply.

The above mentioned and further objects and advantages of our invention and the manner of obtaining them will be more fully set forth in the following description taken in conjunction with the accompanying drawings.

In the drawings, Fig. 1 illustrates one embodiment of our invention wherein two radio receivers are used as an intercommunication system. Fig. 2 represents a modification of the structure shown in Fig. 1, wherein a voice current relay is provided for controlling the circuit of the second receiver, and Fig. 3 illustrates a still further modification of our. invention, wherein a single radio receiver serves by means of a hybrid coil connection, both to reproduce at two loud speakers a radio program and to permit conversation between the two loud speakers. Fig. 4 illustrates a further modification of our invention.

Referring more particularly to the drawings, reference numeral I indicates generally a first radio receiver and 2 a second radio receiver. The first radio receiver has a radio frequency amplifying and detecting stage 3, an audio fre.- quency amplifying stage 4 and a loud speaker 5. In normal use radio signals picked up by the antenna and ground connection pass through the radio frequency amplifying and detecting stage 3 and then travel through conductors 4' and 5 and the back contacts 6 and 'I of relay 8, and conductors 9 and I I) into the input of the audio frequency amplifier 4. The output of the audio frequency amplifier is in turn connected through conductors II and I2, the back contacts I3 and I4 of relay- I5, and conductors I6 and I1 with the loud speaker 5.

Similarly receiver 2 has a radio amplifying and detecting stage I8, an audio amplifying stage I8A and a loud speaker 20. Under normal conditions radio signals picked up by the antenna and ground connections pass through the radio frequency amplifying and detecting stage and then by way of wires 2I and 22 through the back contacts 23 and 24 of relay 25, and conductors 26 and 21 into the input of the audio frequency amplifying stage I8. The output of this amplifying stage is in turn connected through conductors 28 and 29 to the loud speaker 28.

When it is desired to carry on a conversation from loud speaker to loud speaker 20, the key or switch 30 is closed, thereby energizing the winding of relay B through conductors 3|, 32 and 33, battery 34, and the ground return. At the same time, the winding of relay I5 is energized through the conductor and its associated ground connection. By this action the two back contacts of relay 8 are broken as well as the two back contacts of the relay I5. Simultaneously the front contacts 36 and 31 of the latter relay are closed thereby connecting the loud speaker 5 over conductors 38 and 39 with the input of audio frequency amplifying stage 4.

While this operation is taking place the front contacts 48 of relay 8 are closed thereby energizing the winding of relay 25 through conductor 4I and its associated ground connection. 'I'his results in the breaking of the back contacts 23 and 24 of the relay 25 andthe closing of the front contacts 42 and 43 thereof, this operation forms a connection from the output of audio frequency amplifying stage 4 over conductors 44 and 45 with the input of audio frequency amplifying stage I9.

After this series of switching arrangements has been completed the desired conversation can be carried on by speaking directly into the loud speaker 5, which then acts as a dynamic microphone, picks up the sound, passes it to the input is picked 'up by the I of the audio amplifier 4, then through the audio amplifier I9 and into the loud speaker 20 which reproduces the sound. I

If desired, the key 30 may alsobe made to close 'i through suitable relay connections, the energizing circuits of the' radio receivers I and 2-whereby the audio frequency amplifying stages, if not already in use for radio receiving purposes will be rendered operative for intercommunication purposes. As has' been explained hereinabove, while it is desirable that the radio frequency and detecting stage of the reproducing receiver be disconnected from the tudio ampliiier during the use thereof as part-of an intercommunication system, this' 'operation may be dispensed with, the voice currents generated by the loud speaker 5 then being superimposed upon the radio program which is reproduced by the loud speaker 20.

Fig. 2 discloses a system similar to that in Fig. 1, except that have been removed and the relay 25 has been placed under the control of a voice current operated relay 46 which is'bridged -across the wires 44, 45 leading to. the contacts of a. relay I5', which upon energization closes a. circuit to the output of the audio-frequency -ampliiler 4.

An additional modification of the system of Fig. A1 has also been made. A relay 50 having contacts-5I and 52 has been provided for supplying the energizing current to the amplifiers 4 and I9 responsive to the closing of switch 30. Upon closure of this switch direct current energy is supplied over wire 53 from battery 34 to the relay`50, thereby closing contacts 5I and 52 thereof. rent from the power reans to the amplifiers 4 and I9 through conductors 54, 55, 56 and 51. At the same time energy is also supplied to the winding of relay I5' thereby closing its contacts.

With the switch 30 closed when a sound wave loud speaker 5, the currents produced are amplified in the stage v4 and then impressed on the wires 44 and 45 thereby causing the operation of relay 46 withthe resultant 'closing of contacts 41 and the energizing of the relay '25 which is preferably ofthe slow release type, by way of wire. 48 and its associated battery 49, and the ground connection. The amplifying stage I9 then acts to amplify the voice currents and reproduce them in loud speaker 20 in the sarne manner as described in connection with Fig. l. As explained above, relay 25 ,is preferably of the slow release type and therefore a momentary reduction oi' amplitude or cessation of sound adjacent the loud speaker 5, which is vacting as a microphone, will not cause -the release ofthe relay 25, this'relay staying energized for a short period of time after the relay 46 opens its contact 41. While a slow release relay will ordinarily be found suicient to prevent undesirable deenergization and reenergization oi the amplifier I9 and resultant clicks or other vinterference in the reproduced sound, other well known equivalent delay arrangements may be used in place of the slow release feature of relay 25 to insure, if desirable, a still longer connection of the amplifier I9 after cessation of sound adjacent to the loud speaker 5. By the aid of the relay 50 it is possible to render the entire system of stations I and 2 opervative to transmit sound from loud speaker 5 to loud speaker 20 upon closure of the key 30 `r hether or not the radio receivers have previouslybeen energized. In the modified circuit armay well be put eration of the relay 46 Manifestly, this circuit the contacts 40 of relay 8 quency amplifyingstage This results inthe application of curl to the radio receiver will rangement shown in Fig. 2, it will be noted that the key 30 has been moved to a position adjacent the receiver 2, although it could be located adjacent to the receiver I, as shown in connection with Fig. 1.

One use to which the arrangement of Fig. 2

or monitoring vsystem between the nursery and living room of a private home. In this case the key or switch 30 being adjacent the receiver 2 in the living room, the circuit to the control relays may be closed at any time when it is desired to listen for sounds in the nursery. This key may be kept constantly closed so a radio program may still be reproduced by receiver 2, this program will be interrupted by opout or any other sound arrangement has many other uses, in the alarm eld and the example givenr is merely for the purposes of illustration.

Fig. 3 shows a further embodimentl of our invention wherein a single receiver is utilized for intercommunication between a. plurality of points. In this figure reference numeral 59 indicates av radio frequency amplifying and detecting stage and 59 an audio frequency amplifying stage. Two loud speakers 60 and 6I are illustrated, these being connected to the output of the audio fre- 59 by way ofthe inter mediate point of hybrid coil 62, and conductors 63. Under normal conditions a radio program may be picked upby the antenna and `vground is to provide a communication that while whenever an infant cries occurs in the nursery.

connection, then amplified and detected in stage 58, passed through the back contacts 64 and 65 of relay 10, amplified at audio frequency in stage 59 and reproduced on 6I. When it is desired to communicate from a position adjacent one loud speaker to the other loud speaker, a local, circuit is closed which energizes the relay 10 and closes the front contacts 1I and 12 thereof, thereby connecting the input of the audio frequency amplifying stage 59 to the series vWinding of the ,hybrid coil 62. The energization ofthe relay 10 may be brought about by means of either keys 13 and 14 locatedadjacent the loud speakers-60 and 6I, respectively. Upon closure of either of these keys the relay 10 is energized by means of battery 15 and the ground return circuit.

. In most instances one of the loud speakers 'will either be located closely adjacent to or be incorporated in the radio receiver while the other loud speaker will be on an extension line located at a remote point, for example, in another room of a house. In this case the relay 10 and the operating keys 13 and 14 may-be dispensed with, the series winding of the hybrid coil then being connected permanently across the input of the amplifying stage v 59 while the latter is still connected to the output of the radio frequency amplifying both loud speakers Eiland and detecting stage 58. The reason forthis .is

duce aV radio program and intercommunication between the two loud speakers is desired, a per. son Within the range of the loud speaker adjacent be able to operate 4the receiver controls,'to detune thecircuits thereotl so that the radio program is no longer picked up v1n suilicient volumen to disturb the two-way terconnection between l'the loud speakers. Ifa person approaches the extension loud speaker remote from the receiver, it will be necessary merely for him to wait for a lull in the program to announce that he wishes to communicate with v connection whereby 4a person at the other loud speaker and at the same time request that the radio receiver be detuned to eliminate the program. Or, attention may be obtained by tapping on the diaphragm of the extension loud speaker or otherwise making a distinctive sound which will be recognized at the loud speaker adjacent to the receiver.

While we have shown two loud speakers interconnected by means of a single hybrid coil it will be obvious to one skilled in the art that a greater number of loud speakers may also be incorporated in the system by means of additional hybrid coil connections, while at the same time assuring the desired two-way communication between any two loud speakers without interruption of a revceived radioV program. Or, if desired, control keys may be provided adjacent to each loud.

speaker; as shown in Fig. 3.

Fig. 4 shows the circuit of Fig. 3 with the relay 1li and its associated connections removed. In this be used for the reception of programs while at the same time being constantly in readiness for intercommunication between the two loud speakers.

In this specification where reference'has been made`to radiov receivers, it should be clear that tion is applicable to intercommunication between differentl parts of private homes, stores, hotels or other locations wherein one orl several audio frequency amplifiers and several loud speakers are I available.

by use of said loud-speaker last mentioned as a microphone, are conducted to the input of the audio frequency amplifying stage of the other of said receivers.

2. A combined radio receiving and interconmunication system comprising two radio receivers g each having a loud speaker and at least one of said receivers having Aan audio-frequency amplifying stage, and switch means for simultaneously disconnecting the loud speaker from one of the receivers and connecting it to the input of the audio frequency amplifying stage of the other of said receivers.

3. A combined radio receiving and intercommunication system comprising a first and a second radio receiver each having an audio frequency amplifying stage and a loud speaker, the latter being normally connected to the output of the said amplifying stage, and switch means for simultaneously changing the connection of the loud speaker of the first receiver from the output case, as described above, the receiver may munication system comprising a rst and a second radio receiver each having anv audio ffrequency amplifying stage and a loud speaker, the latter being normally connected to the output of the said amplifying stage and switch means for simultaneously energizing said amplifying stage, changing the connection of the loud speaker of the first receiver from the output to the input of the amplifying stage thereof and connecting the output of said amplifying stage of said first receiver to the input of said amplifying stage of said second receiver.

5. A combined radio receiving and intercommunication system comprising. a first and a second radio receiver, each having a detector stage, an audio frequency amplifying stage and a loud speaker, connected in the order mentioned, and switch means for simultaneously disconnecting the loud speaker from the output of the amplifying stage of said first receiver and the detector from the input of the amplifying stage of said first receiver, disconnecting the amplifying stage of said second receiver from the detector stage thereof, connecting the loud speaker of said first receiver to the input of the amplifying stage thereof and connecting the output of said amplifying stage last mentioned to the input of said amplifying stage of said second receiver.

6. A combined radio receiving and intercomcomprising a radio receiver stage, an audio frequency amplifying stage and a loud speaker, said receiver being positioned at a first location, sound pick-up means at a secnd location, aline interconnecting said pick-up means and said radio receiver, and

amplifying stage.

7. A combined radio`receiving and intercomunication system comprising a detector stage,

and loud speaker of' said 'first radio set, a third relay having normallyclosed contacts interconnecting said detector and amplifier of said second radio set, said first relay having a normally open contact connected in'an energizing circuit for said third relay, the latter having normally open contacts connected to the output of said amplifier of said first radio set. and switch means for simultaneously operating said first and second reiays to an otr normal position.

KENNETH E. STOCKTON. JACOB S. JAMldER. 

